Who I have the same questioned this topic

I have changed my account in-store to my changed last name multiple times in the past, but it has *never* updated in billing.

The problem:  Government systems (IRS) which try to authenticate me against my mobile account name fail.

Also, solutions presented in the Community don't help (if in-store update actually worked) since I have moved, am disabled and the closest company store is now an hour+ drive.

Solutions presented also state that a valid photo ID in the old/new name must be shown to effect the name change.  Most organizations, including gov't agencies will accept a certified legal name change document i.e. marriage license, etc, along with the photo id with new name; or accept  a paper trail of the name change (certified: birth cert+name change doc).  Why won't you?  Your systems which don't update and your overly narrow update policies/channels impede progress and function and are a disservice to your customers.

Also, please note: there is a posted question in the community in one of the name change threads that has gone unanswered since 5/27/19.  I usually rave about Verizon's superior customer service, but the community administrators have missed the mark here.